IPhone battery draining quickly?

I have an iPhone 5 and the battery seems to be draining quickly. I left it at home this morning with 100% charge and when I came home 6 hours later it had gone down to 65% and there was no apps running in the background, my phone has only been doing this for the past few days do any help will be appreciated.

Added (1). The sad individual: I've had the phone for about 8 months now

I'm not sure how long you have this phone, but I try to help.

Do you shut off your phone when you go to bed or something?
Do you overcharge your phone sometimes?

These are things that are making the battery drain.

Cell phone battery discharge can happen for lots of reasons. Smartphones can have apps running in the background - you said this is not an issue. Another big power user is the radios in the phone. In the case of the phone, there's the cell-phone radios (for phone calls), Wi-Fi, blue tooth…

Even if the phone is "not being used" these radios are looking for information that might be for them.

In your "settings" area, you can turn off Blue Tooth if you don't use it. If personal hot-spot is on, turn it off when it is not in use. Under "Privacy" then location services, that is OK to have ON… But check the apps that are on - turn off those you do not want on…

Reducing radio use will help prolong battery life…